Checker brick



Jan. 28, 1-930. w. w. ODELL 1,745,113.

CHECKER BRICK Filed Sept. 25. 1926 Q RN [nven for I7 Ii 7 Patented Jan. 28, 1930 PATENT OFFICE WILLIAM W. 015E141, OF MINNEAPOLIS, MINNESOTA i CHECKER BRICK Application filed September 25, 1826. Serial No. 187,740.

My invention relates to an improvement in i the checker brickscommonly used in enriching chambers or in gas generators in making such gas as carburetted water-gas, oil-gas and the like and briefly comprises a tubular refractor with a wall thinner than commonly employe fire bricks and of short tubularlength.

The objects of my invention are, to:

.1. Increase the surface of checker bricks per unit volume of space in thecarburetting chambers and oil-cracking chambers of combustible-gas generating-sets without increasing the resistance to the passage of gas through said chambers and without decreasing the void space therein.

2. Increase the heat available without excessive fluctuations in the temperatures of the checker-bricks in gas-making chambers.

' 3. Eliminate deposits of carbonaceous material and the resultant stoppage of gas passages in the checker-chambers of gas-making apparatus.

4. Increase the oil-gasification elficiency in making carburetted water-gas, oil-gas and the like.

5. Increase the heating surface and contact surface in the carburetting chambers of gas generating apparatus.

6. Provide a readily adjustable contact medium for contacting moving fluids with solid surfaces in confined chambers affording maximum available solid surface per unit of chamber volume.

i 7. Provide checker bricks which can be placed and spaced in checker chambers in a variety of ways without appreciably altering the size of the gas passages through the mass of checker bricks; the surface and volume of checker bricks being the chief variables.

In common practice making oil-gas and in carburetting water-gas or other gas of low calorific value, oil or other carburetting material is introduced, as a spray or mist, into 45 one or more chambers filled with spaced firev brick which are heated to a redetermined temperature judged to be suita le for gasifying the oil. The temperatures of the surfaces of the checker bricks are carefully controlled pyrometrically. In making oil-gas having a calorific value of 550 B. t. u. per cubic foot the commonly preferred temperature is 16501 to 1750 degrees Fahrenheit whereas in carburetting water-gas to the same heating value the oil-gas portion of the latter is richer- (higher in calorific value per cubic foot)- and a suitable temperature is 1350 to 1450 degrees Fahrenheit. In each process the gas is made intermittently and in cycles; the checker'bricks are heated during one part of 9 the cycle and carburetting material is introduced during another part of the cycle. Now, the modern tendency to increase the gas-mak-- ing capacity of such generating apparatus hasresulted in short and intensified heatingperiods, short cycles and increased rate of introduction of the oil or'carburetting material. Also, fewer checker bricks are used per unit of Volume in the checker chambers than formerly in order to increase the capacity by decreasing the resistance to gas flow. A point has been reached in thus decreasing the length of a cycle in the manufacture of city-gas where the surfaces of the checker bricks are cooled during the gas-making period faster 5 than the heat can be carried from within them to the surface. Likewise during the heating period when the checker bricks are being heated the time allowed is so short that their surfaces are overheated and the interior is insufiiciently heated. In other words, in present practice in making city-gas the full heat capacity of the checker bricks is not utilized because their shape and thickness is not suitably adjusted to meet the prevailing methods of operation. Furthermore, the spacing of these bricks has been increased, for reasons stated and to prevent the excessive accumulation of. carbonaceous material-and blown over solid fuel, to such an extent that there is commonly insufficient checker-brick surface in the checker chambers to suitably crack the carburetting material. This is clearly shown by excessive gum and resin deposits in gas meters and pipe lines, by the oil-cracking efficiency-(oil-gasification efliciencv)-and by the decreased specific gravity of the tar which latter usually contains an increasing percentage of saturated hydrocarbons as the oil-gasification efliciencv decreases.

to space them closer. The closer these bricks are spaced the more frequently they must be removed and cleaned, and the less the gasmaking capacity per unit of time, other things being ual, because of the increased resistance to t eflow of gas through the checker chambers. It should be noted that the oil-gasification. efliciency decreases rapidly as the deposit or accumulation ofcarbonaceous matter increases in the mass of checker bricks.

I have tried to use thinner checker bricks to accomplish my purpose but found that more labor was required to lace them in and remove them from the chec er chambers and that difliculty was experienced in maintainin them in position. I find that'hollow or tu ular bricks, ofa different size than firebricks which are commonly used for this purpose, are ideally suited for this purpose their walls should referably be thinner than two and one-half inches.

Figure 1 is a vertical elevation of a carburetted-water-gas set with a portion of the rincipal shells cut awa to show the interior in section, and shows t e checker chambers containing tubular checker bricks arranged in flue formation; Figure 2 is a perspective view of a tubular checker-brick with a ortion cut away to show the wall in section; Figures 3 and 4. are top views of modified forms of tubular checker-bricks which are suitable for this purpose; Figure 5 is an elevation of a chamber containing spaced checker bricks of the ordinary" variety; a portion of the wall is cut away to show the interior in section and to illustrate the two commonly employed methods of spacing and placing checker bricks; Figure 6 is a top view of tubular checker bricks such as shown in Fig. 2, arranged in flue formation.

In Figure 1, 1 is a water-gas generator containing solid fuel 2 and havln steam connections 3 and 4,- fuel chargingoor 5, air inlet for air-blastin the fuel at 6, oiftake connections at 7 and 8 leading to the carburetor. A means for introducing carburetting material into carburetor 9 is shown at 10. The.

carburetor is connected to the superheater 11 and each of these two chambers contain a mass of checker bricks as shown at 12 and 13. Ofitakes are provided in the su erheater for waste blast-gas and carburette gas respectively at 14 and 15. The secondary air inlet to carburetor is shown at 16. The superheat- -er stack-cap is shown at 23.

In Figure 2 the checker-brick substance shown at 17 is substantially the wall of a ve short tube orconduit the interior of whic is shown at 19." A portion of the Wallis shown in section at 18.

In Figures 3 and 4, employing the same system of numbering, as in Fig. 2, the'shapev of the tubular wall is shown for modified forms of tubular checker-bricks.

In Figure 5 shell 20 contains ordinary fire bricks(checker bricks) -spaced in flue fornagtion at '21, and in staggered formation a 2.

In Figure 6 one method is shown of s tubular checker bricks which are su stantially elliptical in horizontal cross sections. The checker bricks shown have flat parallel sides and the ends, as shown, form a semicircle. The same system of numbering is used as in the previous figures.

The outside maximum length of the check 'e r bricks shown in Figures 2 and 6 is substantially equal to twice the inside width plus twice the wall thickness. The sizes of my tubular checker bricks are not limited to any fixed values. However, I find that for bricks having a definite 'wall thickness there are preferred sizes for different referred spacing. Thus with a tubular brick as shown in Figures 2 and 6 having a wall thickness of one and one-half inches the preferred dimensionslength and widthare substantially as follows:

Len h, Minimum outs de Width, inside 1 dimensions outside diameter For 2 inch spacing 7 inches 5 .nches 2 inches. For 3 inch spacing 9 inches..- 6 .nches 3 inches. For 4 inch spacing 11 inches 7 inches... 4 inches. For 5 inch spacing 13 inches 8 ..nches 5 inches. For 6 inch spacing 15 inches-.. 9 inches" 6 inches.

acing v more, or even with some of the smaller sizes,

it may be desirable to provide a wall thicker or thinner than one and one-half inches, in

which case the flpreferred size of the bricks is somewhat di erent with respect to length and width, which dimensions should be in-. creased or decreased as the wall thickness is increased or decreased, by an amount equal to twice the increment, from the values given above for preferred sizes. For example, the preferred length and width of a tubular checker brick having a two-inch wall, for three inch spacing are respectively 10 inches and 7 inches with an inside tubular diameter of 3 inches. The hei ht-tubular lengthcan be any dimension rom a few inches toa foot .or even more. The use to which the bricks are put and the effect desired have bearing upon the selection of a preferred height. For use in gasgenerating a paratus it is convenient to make these bricks about four and one-half inches high equal to the width of standard fire brie s. One advantage in making them this size or a multiple thereof is: they can be used conveniently in conjunction with fire bricks when thus made.

It is obvious that my checker bricks, as shown in Figures 2 and -6 can be arranged in flue formation or in staggered formation similarly as the commonly employed fire bricks. It will be seen that by variously arranging the former, or by spacing them widthwise a distance apart unequal to the internal tubular diameter, effects are produced which it is difficult if not impossible to obtain with fire bricks. In Figure 6 the bricks are arranged contacting one another at their ends but this is not necessary; they may be spaced a predetermined distance apart endwise as desired. Because of the shape of my bricks they can be arranged in this manner without weakening the whole structure-(mass of arranged checker bricks)-whereas greater consideration must be given to this point when using ordinary fire bricks which are approximately 2 by 4 by 9 inches in size. My bricks are particularly well adapted therefore, for use in checkering flash type waste-heat-boilers in which steam is generated and superheated by the heat intermittently stored in massed checker-bricks. In such apparatus a large part of the transfer of heat energy is performed in particular portions of the boiler and in such portions it is obviously desirable to increase the heat storage-capacity by a closer spacing of the checker bricks.

With ordinary fire bricks spaced three inches apart with ends contacting as in common practice the percentage of void space equals (3X100) +(2.5+3) or 54.5. With tubular checker bricks as shown in Figures 2 and 6 spaced three inches apart and end to end the void space is approximately 63.4 per cent. The difference 63.4-54.5 is 8.9 and the latter figure represents a percentage increase of 16.3 inthe void space. The surface exposed with the fire bricks spaced 3 inches apart is approximately 820 square inches per cubic foot of space in the checker. chamber whereas with the tubular checker bricks as above the surface exposed is approximately 980 square inches per cubic foot of chamber space. The difference, 980-820 or 160 represents an increase of 19.5 per cent in the sure face exposed, upon changing from fire bricks to the tubular checker bricks shown in Figures 2 and 6.

Obviously the volume of solid refractory per volume of chamber space is less with the tubular checker bricks than with common fire bricks. It will be noted that with short heating and cooling cycles the temperature in the middle of a thick brick does not fluctuate appreciably if at all hence the actual heatcarrying capacity of my brick under these conditions is not diminished by this decrease in volume ofrefractory. Her -':e in making oil-gas or carburetted water-gas it is possible,

by the use of tubular checker "bricks, to increase the as-making capacit oil-cracking efficiency, t e volume of voi space in the mass of checker bricks and the total amount of checker-brick surface per unit of chamber volume and to decrease the difficulty experienced by stoppages in the mass of checker bricks.

It will also be noted that a greater per.- centage of the exposed surface is active surface with tubular checker bricks than with fire bricks.

The preferred shape of m checker brick is substantially as shown in igures 2 and 6; the sides being flat andarallel and the ends being circular. This orm has advantages over bricks which are truly elliptical in cross section for reasons which are apparent upon arranging them in a checker chamber. However it is recognized that tubular bricks having a cross section which is substantially rectangular, octagonal, hexagonal, circular, elliptical or the like is superior to common fire bricks for checkering purposes. Believing that the use of short tubular checker bricks is new in gas making processes the claims are written with the intent to broadly cover this point.

Attention is called to the fact that in times past the lengthof the operating cycle, in making carburetted water-gas and the like, was twenty-five to forty-five minutes; about half of this time being used for heatingthe checker bricks and the remainder forthe gasmaking period during which time the heat stored in the checker bricks is utilized. Under these conditions sufficient time was allowed for the full utilization of the heat capacity of fire bricks or similar solid checker bricks. At present the length of a complete cycle is five to six minutes, consisting in a two minute heatingperiod and a three to four minute gasmaking period, the carburetting material being added during two to three minutes ofthe gas-making period. During the latter period the oil is injected so rapidly that the surfaces of theordinary checker bricks become cooled below a satisfactory gas-making temperature even though considerable heat is still stored in these bricks. The essential requirement in this process is that there be plenty of exposed checker-brick surface heated to a gas-making temperature. The desirability of increasing the amount of checker-brick surface in gasmakin'g checker chambers is largely the result of the recent changes in the operating cycle and the increased rate of making gas. The need for this increased surface area is generally recognized among gas engineers who also understand that ordinary fire bricks can not be thus arranged without causing deleterious effects.

In common practice the blast-gas used for heating the checker bricks in making carburetted water-gas varies in composition during the brief blastin period. At the start it is composed chiefly 0 nitrogen and carbon d1- oxide with very little combustible matter, becoming richer as the generator blastin is continued, finally reaching a maximum value of 110 to 135 B. t. u. per cubic foot at the end of the blast eriod. The flame temperature in the chec er chambers is too low to impart suflicient heat to th1ck checker bricks of relativel small surface-volume ratio in the usual brief blasting period. I find that a greater amount of heat energy can be transferred per unit of time during the different portions of the operating cycle when tubular bricks are used having a surface-volume ratio greater than that of fire bricks.

The substance of which my checker bricks are composed may be an solid material capable of being shaped as escribed. Obviously they must be made of refractory material when intended to withstand high temperatures such'as prevail in the gas-making chambers of carburetted water-gas sets or oil-gas sets. The term refractory material as used here includes metals.

My checker-brick when spaced and arranged in formation in a checker chamber for use in heat exchan e are in reticular formation; by reticular ormation I means the structure is ,a net work of checker-bricks. This differentiates the structure from recuerators and similar structures in which holow tile are commonly placed end to end making continuous conduits and not a reticular or network structure. The fact that my bricks are arranged in a net-like structure does not completely differentiate m structure from that of a recuperator throng which a gas may pass in one direction within tubular channels and in an opposite direction on the outer side of said channels. By reticular formation I refer to a articular network of checkerbricks, name y, that in which the bricks are spaced and arranged in a network formation com rising a plurality of superposed courses. TheIaricks are s seed and arranged in the different courses. They are spaced and arranged in such a manner that the bricks of one course are not tubularly continuous with those of adjacent courses. Thus the bricks as arranged in my structure are tubularly discontinuous whereas in recuperators they are arranged to be tubularly continuous. In other words the bricks are so arranged in my structure that their ends (tube ends) do not symmetrically contact one another. A fluid passing through this structure is not confined to either the inner or outer side of the bricks but-may contact the inner side of some of the bricks and the outer side of others.

eating thin walls of substantially uniform thickness and arranged in reticular formation in substantially parallel spaced relation to form a plurality of superposed layers, each superposed layer having its bricks angularly disposed with relation to the bricks of adjacent upper and lower layers.

2. In a checker-brick device comprising a plurality of spaced and arranged checkerricks, said bricks being substantially short, flattened, refractory tubes having thin walls of substantially uniform thickness and arranged in reticular formation in substantially parallel spaced relation toform a plurality of superposed layers, each superposed layer having its bricks angularly disposed with relation to the bricks of ad acent upper and lower layers; said layers collectively forming a plurality of parallel tubes having discontinuous walls and a plurality of substantiallyv parallel channels the walls of which are discontinuous comprising the outer walls of said bricks.

3. In a checker-brick device comprising a plurality of tubular, spaced and arranged checker-bricks, said bricks being substantially short, flattened, refractory tubes having thin walls and arranged in reticular formation in substantially parallel spaced relation to form a plurality o superposed layers, each layer having its bricks angularly disposed and tubular] discontinuous with relation to the bricks 0' adjacent upper and lower layers.

4. In a checker-brick device comprising a plurality of tubular, spaced and arranged checker-bricks said bricks being substantially short, flattened, refractory tubes having thin walls and arranged in reticular formation in substantially parallel spaced relation to form a plurality o superposed layers, each layer having its bricks angularly disposed and tubularly discontinuous with relation to the bricks of adjacent upper and lower layers; substantially each of said arranged bricks in said superposed layers bein supported by and contactin a ortion of the walls of four of the bricks in t e next lower layer.

5. In a checker-brick device comprising a plurality of spaced and arranged tubular checker-bricks, said bricks being substantially short, flattened, refractory tubes, having rounded end-walls and substantially flat sidewalls and arranged with their tube-axes substantially vertical in reticular formation in substantlall parallel spaced rows to form a plurality of superposed layers, each of said superposed layers having its rows angularly disposed with relation to those of adjacent upper and lower layers and spaced a distance substantially equal to the short inside diameter of said refractory tubes, the bricks of each layer being tubularly discontinuous with those of ad'acent layers.

6. In a c ecker-brick device com risin a plurality of spaced and arrange tubu ar checker-bricks, said bricks bein substantial,- ly short, flattened refractory tu es, having a wall thickness :0 and an inside shortdiameter y, an outside long-diameter substantially e ual to (2;; +2w) an outside 'sh'ortdiameter su stantially equal to (QaH-y) andarranged in reticular formation ,in substantially parallel spaced rows to form a plural-ity of superposed layers, substantially each layer having its rowsangularly disposed with relation to those of ad acent upper and lower layers. I y I 7. In a checker-brick device com rising'a plurality of spaced and arrange tubular checker-bricks, said bricks being substantially short, flattened, open, tubes having a Wall thickness w, an inside. short-diameter y, an outside long-diameter substantially equal to (Qy-t-Qda), and an outside shortdiameter substantially equal to ('Zw-l-y), arranged vertically tubularly in substantially reticulated formation comprising a plurality of superposed courses.

WILLIAM W. ODELL. 

